Production of acrylic acid and its salts



Feb. 16; 1960 w, REPPE ETAL PRODUCTION OF ACRYLIC ACID AND ITS SALTS Filed Feb. 15, 1957 ABSOLUTE AmosPHEREs IN'VENTORS WALTER REPPE FRANZ REICHENEDER GUENTHER STENGEL BY ALBERT ZlEGER ATTORN 3v because satisfactory space-time yields are also obtained in the absence or activators.

The process may be carried out discontinuously or continuously. The carbon monoxide used in excess can be partly or wholly 'decoriipressed and, after'the addition of acetylene or mixtures rich in acetylene, can be'r'ecompressed to the reaction pressure and supplied "to the re; action'chamber.

The following examples will further illustrate this invention but the invention is not restricted to these examples.

Example I 400 ccs. of a solution having the following composition: 3400 grams of water 46.7 grams of nickel sulfate (NiSO .7H O) 60 grams of potassium cyanide and 387 grams of'anhydrous sodium carbonate are pumped per hour upwardly through a verticallyarranged stainless steel .tube capable of withstanding high pressure which has a capacity of 11 liter. At the same time a gas mixture of 17% by volume of acetylene and 83% by volume of carbon monoxide is led through the tube under 200 atmospheres absolute. The reaction temperature is adjusted to 245 to 250 C. by electrical heating. 700 liters of gas, mainly consisting of carbon monoxide, are released from pressure per hour. Each day 9.6 liters of water containing catalyst are charged into the tube and 13.5 to 14.5 liters of product recovered from which the acrylic acid is isolated in the usual way. average of to 6 kilograms of pure acrylic acid are obtained from the daily product by distillation.

Example 2 A solution of 41 grams of nickel sulfate (NiSO .7H O) and 45 grams of sodium cyanide in 4500 grams of water is pumped through the same arrangement as in Example 1. At the same time a gas mixture of 19% by volume of acetylene and 81% by volume of carbon monoxide is led through the tube at 200 atmospheres absolute. The reaction temperature is adjusted to 260 to 270 C. by electrical heating. 1000 to 1200 liters of gas per hour are released from pressure. Each day 24.0 liters of catalyst solution are charged into the tube and 30 liters of product recovered from which up to 10 kilograms of acrylic acid can be isolated in the usual way.

Example 3 10 liters of a solution of 400 grams of nickel acetate in -8 liters of water are pumped upwardly each hour through a vertically-arranged stainless steel tube of 3 liters capacity, which is capable of withstanding high pressure. At the same time a gas mixture of 20% of acetylene and 80% of carbon monoxide is led through the tube under 200 atmospheres absolute. The reaction temperature is kept at 280 to 290 C. by electrical heating. Each hour 6000 liters of gas consisting mainly of a mixture of carbon monoxide and acetylene with 13% of acetylene are released from pressure. The decompressed gas can be led into the reaction vessel again after the admixture therewith of acetylene. Each day 240 liters of water containing catalyst are charged into the tube. From a product of about 270 liters per day, about 46 kilograms of acrylic acid can be isolated by distillation.

Example 4 A nickel acrylate solution which contains |1.8 grams of nickel to one liter of solution is pumped through a three liter vertical high-pressure container of stainless steel from bottom to top at a rate of liters per hour. .At the same time a gas mixture of by volume of acetylene and 80% by volume of carbon monoxide is fed in from the bottom at a pressure of 200 atmospheres Hg. 7 cubic meters (NTP) of a gas mixture which still contains 15% of acetylene are" expanded per hour through the container head. Another 4 cubic meters (NTP) of this gas are refed into the container as a cycle gas from below by means of a gas pump at a pressure of 200 atmospheres. The expanded gas, the acetylene content thereof having been raised to 20%, can be recycled for furtherreaction.. I

The reaction temperature is set to 280 to 290 C. by electric heating.

The amount of catalyst solution pumped into the container is 240 liters per day. The output amounts to 275 liters from which 48 kilograms of acrylic acid are isolated. I

Example 5 A solution of nickel adipate which contains 1.8 grams of. nickelto one liter is pumped through a container ofv the type described. in Example 4 together with a gas mixture of 20% by volum'eof acetylene and by volume of carbon monoxide which is fed in at a pressure of 200 atmospheres Hg. The reaction temperature is set to 280 *to 290 C. The quantity of gas expanded amounts to 1.200 to 1.500 liters per hour. With 19.2 liters of catalyst solution put in per day 22.7 liters of output were obtained from which 7.5 kilograms of acrylic acid can be isolated per day.

Example 6 Using a container of the type described in Example 4 a solution of nickel citrate containing 1.8 grams of nickel to one liter is fed in at a rate of 19.2 liters per day. The output of the reaction amounts to 21.8 liters per day from which 7.0 kilograms of pure acrylic acid can be isolated. Example 7 With the container being the same as in Example 4 a solution of nickel sulfate which contains 1.8 grams of nickel is fed in at a rate of 19.5 liters per day. From the output of 22.3 liters per day 5.5 kilograms of pure acrylic acid can be isolated.

We claim:

1. In a process for the production of an acrylic compound selected from the group consisting of free acrylic acid and its alkali metal salts by the interaction of acetylene, carbon monoxide and water in the presence of a nickel compound as carbonylation catalyst, the immovement which comprises carrying out said reaction at a minimum pressure of 75 atmospheres absolute'but below the decomposition limiting pressure of the mixture of acetylene and carbon monoxide at a temperature between 180 and 300 C.

2. In a process for the production of an acrylic compound selected from the group consisting of free acrylic acid and its'alkali metal salts by the interaction of acetyl-' ene, carbon monoxide and water in the presence of a nickel compound as carbonylation catalyst, the improve ment which comprises carrying out said reaction at a minimum pressure of 75 atmospheres absolute but below the decomposition limiting pressure of a mixture of acetylene and carbon monoxide containing between 10 and 23% by volume of acetylene at a temperature be tween 220 and 300 C.

References Cited in the file of this patent UNITED STATES PATENTS Patent No. 2,925 436 Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION February 16 1960 Walter Reppe et al. I

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, between lines 7, and 8 thereof, insert Claims priority, application Germany February 24, 1956 Signed and sealed this 20th day of December 1960,

(SEAL) Attest:

KARL H. AXLINE Commissioner of Patents ROBERT c; WATSON 

1. IN A PROCESS FOR THE PRODUCTION OF AN ACRYLIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF FREE ACRYLIC ACID AND ITS ALKALI METAL SALTS BY THE INTERACTION OF ACETYLENE, CARBON MONOXIDE AND WATER IN THE PRESENCE OF A NICKEL COMPOUND AS CARBONYLATION CATALYST, THE IMPROVEMENT WHICH COMPRISES CARRYING OUT SAID REACTION AT A MINIMUM PRESSURE OF 75 ATMOSPHERES ABSOLUTE BUT BELOW THE DECOMPOSITION LIMITING PRESSURE OF THE MIXTURE OF ACETYLENE AND CARBON NONOXIDE AT A TEMPERATURE BETWEEN 180* AND 300*C. 